JP7079324B2 - Skin sensor - Google Patents

Description

The present invention relates to a system comprising a sensor for measuring skin parameters such as skin gloss. The present invention further relates to a method for evaluating skin parameters such as skin gloss.

Skin analysis is known in the art. For example, Patent Document 1 describes a system for collecting, storing, and displaying dermatological images for the purpose of monitoring and diagnosing skin cancer including skin symptoms and melanoma. A handheld unit illuminates a portion of the patient's skin, and an imaging device produces an imaging signal from the light obtained from the portion of the skin. The pair of optical output ports within the handheld unit are arranged so that the resulting sum of their intensities has a flat central portion because their intensity distributions overlap at half that intensity level. The storage of three images is maintained, one for the lesion image, one for the "near skin" image, and one for the reference white image. Images "near the skin" are used by system software to automatically determine skin / lesion boundaries. The reference white image is used to set the dynamic range of the device and to compensate for uneven illumination. Since two images of the same lesion taken at different times can be displayed simultaneously, changes in the lesion can be determined. The calibration system is designed so that image data acquired on any of multiple machines built with the same specifications is corrected to return to a common reference standard to ensure absolute color reproduction accuracy.

Patent Document 1 describes a system for collecting, storing, and displaying dermatological images for the purpose of monitoring and diagnosing skin cancer including skin symptoms and melanoma. A handheld unit illuminates a portion of the patient's skin, and an imaging device produces an imaging signal from the light obtained from the portion of the skin. The pair of optical output ports within the handheld unit are arranged so that the resulting sum of their intensities has a flat central portion because their intensity distributions overlap at half that intensity level. The storage of three images is maintained, one for the lesion image, one for the "near skin" image, and one for the reference white image. Images "near the skin" are used by system software to automatically determine skin / lesion boundaries. The reference white image is used to set the dynamic range of the device and to compensate for uneven illumination. Since two images of the same lesion taken at different times can be displayed simultaneously, changes in the lesion can be determined. The calibration system is designed so that image data acquired on any of multiple machines built with the same specifications is corrected to return to a common reference standard.

Patent Document 2 describes a dermatoscope in the form of a handheld device. The dermatoscope stores a display placed in or on the housing and an image recorded by the dermatoscope for an image of the skin surface and / or the structure of the skin surface recorded by the surface sensor of the dermatoscope. Includes storage means.

Patent Document 3 describes an imaging device including a lens optical system L, an imaging device N including a plurality of first and second pixels P1 and P2, and an aligned optical device K: lens optics. The system L includes a first optical region D1 that mainly passes light oscillating in the direction of the first polarization axis and a second optical region D2 that allows light that oscillates in all directions to pass; further, alignment. The forced optical device K causes the light that has passed through the first optical region D1 to be incident on the first pixel P1 and the light that has passed through the second optical region D2 to be incident on the second pixel P2.

Patent Document 4 describes a transparent sheet having an upper surface configured to accommodate the sole of the foot, a light source arranged under the sheet and emitting light toward the sheet, and light directed toward a predetermined foot area. Devices and methods for image processing of the human foot, including an optical path controller in or coupled to a sheet for altering the path of light that causes internal reflection. The image can be analyzed for certain characteristics associated with the human patient and can further determine if the characteristics in the image match the patient. Brightness in images can be analyzed for tissue moisture information.

Patent Document 5 describes a glass product having an anti-glare surface. The anti-glare surface has a reflected image sharpness of less than 95 and a haze of 50% or less. In one embodiment, the glassware further comprises a smudge-resistant surface disposed on an antiglare surface. It also describes how to make glassware and anti-glare surfaces.

Patent Document 6 describes a lighting unit capable of switching the illumination direction to an object, adjusting the focus on the object for all the illumination directions, calculating an evaluation value according to a focus state, and further, focusing based on the evaluation value. An imaging device including a control unit that determines the direction in which the state is the best as the illumination direction and captures the object is described.

Patent Document 7 is for controlling the rotation angle of the synchrotron radiation polarizing surface with respect to the incident light polarizing surface and the polarizing element 35 arranged between the camera 31, the light source 32, the camera 31, the light source 32, and the subject 11. Describes an imaging apparatus including a spatial optical modulator 40A disposed between a polarizing element 35 and a subject 11.

Patent Document 8 describes a method for determining the boundaries of lesions on the skin. An image of the skin area containing the lesion is captured. An annular variance test is performed on the pixels around the lesion. Based on the results of the circular dispersion test, either the seed region expansion method or the color clustering method is applied to the image to calculate the lesion boundaries. The color cluster method can generate multiple selectable boundaries. Lesion boundaries that will be manually traced are also prepared.

Patent Document 9 describes a portable device for observing typological characteristics of the body. For example, the device can be used to observe at least one characteristic of the appearance of the skin or hair. The device can generate at least two images of the zone being inspected. The images differ from each other in terms of features other than the intensity and magnification of the light source.

U.S. Pat. No. 6,993,167 U.S. Patent Application Publication No. 2013/0053701 U.S. Patent Application Publication No. 2014/0055661 U.S. Patent Application Publication No. 2014/01214479 U.S. Patent Application Publication No. 2010/0246016 U.S. Patent Application Publication No. 2013/02565505 International Publication No. 2015/174163 International Publication No. 02/094097 U.S. Patent Application Publication No. 2003/0045799

The appearance of the skin is significantly affected by the presence of a thin emulsified film on the surface of the skin. Sebum with lipids from the sebaceous glands and epidermal keratinized cells is mixed with sweat and other lipids from cosmetics and the environment to form this emulsified membrane with a higher refractive index than the epidermis. Sebum makes the skin appear more shiny due to its stronger Fresnel reflections and smooth air-sebum interface. The optimal balance between sebum production and requirements is one that gives the skin a dull, healthy feel and is dermatologically and cosmetically desirable. Shiny and greasy skin is considered unaesthetic and unpleasant and is often associated with a variety of dermatological disorders such as seborrhea, acne and hormonal imbalance. In a sebum-deficient state, the skin is vulnerable to infection, itchy and dry, dull, erythematous, and visible.

As a result, by controlling the rate of sebum secretion, balancing skin requirements with its optimal lipid requirements and / or monitoring skin condition using non-invasive optics and methods. It seems that a strategy is needed.

For home use, especially in environments such as bathrooms, the sensor is expected to be waterproof and clean. This can be achieved by using a transparent glass window that shields the entire illumination and detection optics. With a skin sensor such as a dermatoscope, the glass window can be placed in contact with the skin. However, when the glass window is used in contact with the skin, the sensor signal is dominated by "ghost spots" resulting from Frenel reflections at the two interfaces of the glass window (air-glass and glass-air interface). Seems to be. This ghost spot does not carry any information from the sample (skin) and is called an "undesirable reflection". For a given lighting condition, the ghost spot is expected to be stronger than the light reflected from the skin due to the higher reflectance coefficient of the glass-air interface compared to the effective reflection generated from the skin. In addition to this, ghost spots from the glass can interfere with and overlap with signals coming from the skin, resulting in poor skin oil / gloss estimates. It becomes.

Devices for measuring skin gloss (or "skin gloss") are known in the art. However, such equipment is not available for (reliable) home use. In addition, the device may suffer from unwanted artifacts such as specular spots that can affect the reliability of reflection measurements.

Thus, preferably, an alternative device that at least partially eliminates one or more of the above drawbacks (where more, the more general term "system" applies) and / or skin. It is one aspect of the present invention to provide a (glossy) sensing method. The present invention may have an object to overcome or ameliorate at least one of the disadvantages of the prior art, or to provide a useful alternative.

Surprisingly, the use of additional windows at a distance from the skin, between the skin and the detector, and at a distance from the skin, can substantially improve signal reliability. Seemed to be. Such windows have essentially no optical function, such as converging or diverging light rays, but are particularly essentially planar windows.

Among other, the present invention measures one or more of skin parameters, particularly skin gloss, oil and oiliness, and skin hydration, but optionally also a system comprising a sensor to measure hair parameters (“system”). Or "skin sensor system" or "sensor system"), the sensor is composed of (i) a plurality of spatially separated light sources configured to provide light from the light source and (ii) a light source. A detector configured at a first distance (d1) from each, and a first distance (d1), in a particular embodiment, from a range of 5-100 mm, such as 5-80 mm in particular. The sensor may be selected from a range of at least 1 mm, such as at least 2 mm, such as at least 5 mm, such as selected, and the sensor comprises, in particular, at least three light sources, the light source providing light from an unpolarized light source. The sensor is configured to (iii) downstream of the light source and upstream of the detector, for propagation of the light from the light source from the sensor, and at the inlet of the (returned) reflected sensor light into the sensor. A sensor opening for (iv) a sensor window (“window”) of material that transmits light from the light source, (the sensor window) is configured downstream of the light source, upstream of the sensor opening, and further. With a sensor window configured upstream of the detector, the second distance (d2) to the sensor opening is at least 1 mm, particularly such as at least 2 mm, and more specifically at least 3 mm. Further included. In particular, the sensor is configured to provide light from a light source having an optical axis (OL) below an angle (α) with respect to the optical axis (O2) of the detector selected from the range of 10-80 °.

The use of such a system may allow for an essentially fixed distance to the skin, which is essentially equal to the second distance. The sensor opening determines the distance from the skin to the sensor window. At such distances, especially when the distance between the skin and the sensor window is at least 3 mm, artifacts such as ghost spots appear to be substantially reduced. This improves the reliability of the system. In addition, the presence of the window may also allow the sensor to be used in a damp environment. Therefore, a sensor window that does not physically contact the skin under investigation by the system during use is provided.

In particular, the system can be used to measure skin parameters. Thus, the system can be specifically configured to measure skin parameters. Alternatively or additionally, this system can be used to measure hair parameters. Thus, the system can be configured to measure hair parameters alternativeally or additionally (also). Alternatively or additionally, the system can be used to measure parameters of another part of the body, such as to measure part of the eyeball or oral cavity. Thus, the system can be configured to, alternatively or additionally (also), measure parameters of a part of the body that is neither skin nor hair.

Moreover, in such a system, it may be possible to quantitatively estimate skin gloss. The term "skin gloss" as used herein means skin gloss, but can also mean "skin oily". Thus, the term "skin gloss" can also be defined herein as "skin parameters specifically selected from one or more of the groups comprising skin gloss and oily skin". The values that can be measured by the systems described herein may reflect skin gloss and oiliness, as skin gloss may be associated with skin oiliness. Therefore, the term "skin gloss" may be used to indicate both skin gloss or skin oiliness. Thus, in a plurality of embodiments, the term skin gloss may mean skin gloss or oily skin, or in particular skin gloss.

As mentioned above, the present invention provides a system that includes a sensor. The term "system" can mean, for example, a single device having its own housing, but functionally, for example, a sensor and control system, or a control system including devices such as computers, smartphones, and the like. A combined device can also mean. In multiple embodiments, the term "sensor" can also mean multiple sensors.

In particular, the system includes a housing, such as a system that includes a device that includes a housing. The sensor may essentially be housed by a housing. The housing may include a housing opening. Such a housing opening can provide a field of view for the detector. In addition, the housing with the housing opening is the last optical system in front of the housing opening (ie, the skin if the sensor is configured on the skin) and the detector (or (as seen from the detector)). A second distance, which can be defined as a distance to, in particular a lens), can also be provided. The second distance may be expressed as a free working distance, as the distance between the housing opening and the detector, or, where optical system is available, with the housing opening (in the direction of the opening). It may be defined as the distance from the last optical system (as seen from the detector). Thus, the second distance is the operation between the skin and the detector, or, where the optical system is available, between the skin and the last optical system (as viewed from the detector in the direction of the opening). It may be shown as a medium distance. The housing can be viewed as a distance holder to determine the distance between the skin and the detector (or its last optical system). Such an optical system is configured upstream of the detector; that is, the detector is configured downstream of such (arbitrary) optical system. The second distance may be as much as 10-45 mm, but may even be up to 200 mm. Therefore, in a plurality of embodiments, the second distance can be selected from the range of 10 to 200 mm, such as 10 to 30 mm, or the range of 40 to 80 mm.

The detector is configured to detect the reflected light. Therefore, the detector detects reflected light for imaging during (continuous) illumination by a (unpolarized) light source. The detector essentially only detects, for example, the polarization by the modulator upstream of the detector. The optical axis of the detector and the optical axis of the sensor may be essentially aligned. In addition, the sensor optical axis and the net optical axis of all light sources may be essentially aligned (because the light source may be configured symmetrically with respect to the detector).

The light source is specifically located at a first distance from the detector, the first distance being configured to be smaller than the (related) field of view (dimensions). Further, the plurality of light sources may include, in particular, a set of two (or more) light sources configured equidistant from the detector. Such sets can be controlled independently. Moreover, the first distance is not always equal for each of the light sources. Therefore, the expression "detector configured at a first distance (d1) from each of the light sources" and similar expressions are "light sources configured at a first distance (d1) from the light source". The first distance to each of the light sources may be the same, or may be interpreted as "a light source having two or more different first distances". As shown herein, the first distance can be selected, in particular, from the range of 1-100 mm.

In particular, the first distance is the shortest distance between the light emitting surface of the light source and the detector region (or detector surface) of the detector. As shown in the figure, the distance is measured in particular in a plane parallel to the aperture or aperture (cross section) of the sensor or in a plane perpendicular to the optical axis.

Accordingly, the present invention provides a system comprising a sensor (also (also) measuring skin parameters in one embodiment, wherein the sensor is configured to provide light from an (i) (unpolarized) light source. In certain embodiments, the sensor is selected from the range of 10-80 °, including a spatially isolated light source and a detector configured at a first distance from each of the (ii) light sources. It is configured to provide the light of a light source having an optical axis at a given incident angle (α), and during operation, the sensor is configured on the skin with the opening of the sensor housing on the skin. In addition, the sensor is configured to detect the light of the reflected light source (reflected by the skin), the sensor comprises at least three light sources, and the light source is a visible light source. The light of the visible light source is unpolarized, the first distance is selected from the range of 10-80 mm, and the detector is configured to detect the polarized light. To. The system may include additional features as defined in the accompanying embodiments.

The system is a display unit (eg, "processor" or "processor system" or "controller" or "control system"), user interface, and display unit for indicating the sensed skin gloss value, such as a memory, a processing device (or "processor" or "processor system" or "controller" or "control system"), and an LED indicator. , Suitable for indicating different values by switching on 0-n LEDs depending on the sensed value, where n is used to indicate the maximum sensed value. The number of LEDs, where n is generally at least three, etc., 2 or more, etc.), and / or may include a display.

Examples of user interface devices include manually activated buttons, displays, touch screens, keypads, voice-activated input devices, voice outputs, indicators (eg lights, etc.), switches, knobs, modems, among others. And network cards. In particular, the user interface device may be configured to allow the user to direct to a device or instrument to which the user interface is functionally coupled by functionally including the user interface. User interfaces may include, in particular, manually actuated buttons, touch screens, keypads, voice-activated input devices, switches, knobs, etc., and / or optionally include modems, network cards, etc. But it may be. The user interface may include a graphical user interface. The term "user interface" can also mean a remote user interface such as a remote control. The remote control may be another dedicated device. However, the remote control may also be a device with an App configured to (at least) control the system or device or instrument.

The controller / processor and memory may be of any type. The processor may have the ability to perform various described operations and execute instructions stored in memory. The processor may be an integrated circuit for specific applications or an integrated circuit for general applications. Further, the processor may be a dedicated processor for performing according to the system, or may be a general-purpose processor in which only one of many functions is operated to perform according to the system. The processor may operate using a program portion, a plurality of program segments, or may be a hardware device that utilizes a dedicated or multipurpose integrated circuit.

The sensor includes (i) a plurality of spatially separated light sources configured to provide the light of the light source (“light”). In particular, the sensor comprises at least three spatially separated light sources.

The term "light source" may include semiconductor light emitting devices such as light emitting diodes (LEDs), resonant cavity light emitting diodes (RCLEDs), vertical resonator surface emitting laser diodes (VCSELs), end face emitting lasers and the like. The term "light source" may also refer to an organic light emitting diode such as a passive matrix (PMOLED) or an active matrix (AMOLED). In certain embodiments, the light source includes a solid light source (such as an LED or laser diode). In one embodiment, the light source includes an LED (light emitting diode). The term LED can also refer to multiple LEDs. Further, the term "light source" can also refer to so-called chip-on-board (COB) light sources in a plurality of embodiments. The term "COB" specifically refers to an LED chip in the form of a semiconductor chip, such as a PCB, which is neither inserted nor connected but directly mounted on a substrate. Therefore, a plurality of semiconductor light sources may be configured on the same substrate. In a plurality of embodiments, the COB is a multi-LED chip configured together as a single lighting module.

Further, the light source is configured to provide the light of an unpolarized light source. This allows the sensor to obtain information from the polarization direction of the reflected light. Thus, in this system, in certain embodiments, light from an unpolarized light source is provided on the skin.

The light source may be configured to provide one or more of visible and infrared light (particularly near-infrared light). Visible light may be white light. The IR light may be radiation having a wavelength selected from the range of 750 to 3000 nm, for example, particularly selected from the range up to about 1200 nm.

In addition, the light source is specifically configured to provide white light. The term white light herein is known to those of skill in the art and is particularly light having a correlated color temperature (CCT) of about 2000 to 20000K, particularly 2700 to 20000K, and in particular about 2700 to 6500K. For general lighting in the range, and especially for backlight purposes in the range of about 7000 to 20000K, especially within about 15 SDCM (standard deviation of color matching) from BBL (blackbody locus), especially. It may be associated with light within about 10 SDCMs from the BBL, and more specifically within about 5 SDCMs from the BBL. In particular, the white light may be provided by a blue LED having a light emitting material that emits yellow light. Such a light source can provide white light that is essentially unpolarized. Visible light has a wavelength selected from the range of 389 to 780 nm.

In particular, the sensor includes a plurality of spatially separated light sources. This implies that there is some distance between the light sources. In particular, the light source is configured to have a detector in between. Further, in particular, the maximum number of light sources is 10 mag, about 12 such as 3 or 4 or 6 etc., 8. Up to about 12, and more specifically up to about 6, etc., allow placement around the sensor, which also allows spatial separation between adjacent light sources, which is at least 5 mm. Etc., which may be about 1 to 100 mm, such as at least 10 mm.

Therefore, in a plurality of embodiments, the system comprises at least three light sources. In another further embodiment, the sensor has a sensor optical axis and the light source is configured to be rotationally symmetric about the sensor optical axis. In a plurality of embodiments, the light sources may be configured in relation to each other under an angle of 360 ° / n with an optical axis, where n is the number of light sources. Thus, in embodiments where the system includes at least three or four light sources, the mutual angles with the optical axis can be 120 ° and 90 °, respectively.

Thus, as mentioned above, the system particularly comprises at least two light sources, more specifically at least three light sources, which are particularly unpolarized (visible) light sources, even more specifically. Is configured to provide white light.

In a plurality of embodiments, the system may include, in particular, a plurality of light sources that provide light from a visible light source, the light from the visible light source is unpolarized, and in particular the light from essentially all visible light sources. Is unpolarized. In particular, each of the light sources provides light from an essentially unpolarized visible light source. Thus, these embodiments provide light from an unpolarized light source to the skin, and the light from the light source is essentially partially unpolarized. Thus, in particular, the light source is configured to provide the light of a visible light source, and the light of the visible light source is unpolarized.

Further, as described above, the system also includes a detector configured at a first distance (d1) from each of the light sources. Good results were obtained at a first distance (d1) within the range of about 1-80 mm. Thus, in certain embodiments, the first distance is in the range of 1-80 mm, such as in the range of 6-14 mm, 5-20 mm, etc., in particular, in the range of 4-20 mm, in the range of 5-80 mm, etc., in particular. It can be selected from the range of 2 to 60 mm. Therefore, in a plurality of embodiments, the first distance (d1) can be selected from a range of about 4 to 20 mm, such as 6 to 14 mm, particularly about 8 to 14 mm.

In particular, the detector is configured to detect polarized light. For this purpose, the detector may include a modulator configured upstream of the detector. In this way, only polarized light, particularly S-polarized light, can be received by the detector. In the following, some specific embodiments of the modulator will be further clarified.

In particular, the detector is configured to detect polarized light. Therefore, the sensor may include a stator configured upstream of the detector. The modulator sorts the light of a reflected (unpolarized) light source (reflected by the skin) so that the detector receives polarized light, especially S-polarized light, or particularly P-polarized light. can do.

In certain embodiments, the sensor emits light from a light source having an optical axis (OL) at an angle of incidence (α) with the skin at a third distance (d3), specifically selected from the range 10-80 °. It is configured to provide and detect the light of a reflected light source (reflected by the skin). Of course, the skin is not part of the system. However, this system is specifically configured to measure the skin at a third distance. For example, the system may include a distance holder or other element, which allows the configuration of the sensor at a third distance. At this distance, the above incident angles within the range of 10-80 °, especially 20-80 °, can be achieved. In certain embodiments further described below, the angle is selected from the range of 20-60 °.

Thus, in certain embodiments, the sensor is configured to provide light from a light source having an optical axis at an angle (α) with respect to the optical axis (O2) of the detector selected from the range of 10-80 °. To. Further, in a plurality of embodiments, the angle (α) may be selected, in particular, from the range of 20-60 °. The optical axis of the detector / sensor is also referred to herein as the "sensor optical axis".

Thus, in a plurality of embodiments, the sensor may be configured to have the skin, in particular at a third distance (d3), to detect the reflected light from the light source.

The distance holder is configured to be placed on the skin such that the skin is at a second distance from the detector or the last optical system in front of the detector (as seen from the detector). In particular, the distance holder may be configured to be laid flat on the skin so that the skin is at a second distance from the detector or the last optical system in front of the detector (as seen from the detector). good. The distance holder may be included within the housing of the sensor. In particular, the system may include a housing that at least partially surrounds the sensor, the housing including a distance holder. Alternatively, the system may include a housing and (another) distance holder; in such embodiments, the second distance may be further increased. Further, the distance holder other than the housing may include an opening.

At least a portion thereof, such as a system or housing, may be configured to be pressed against the skin. Thus, "on the skin" can indicate that the system or at least a portion thereof is pressed against the skin (during use), in particular a distance holder such as a housing is pressed against the skin. Thus, the term "second distance" specifically refers to the distance between the detector or its last optical system (as viewed from the detector) and the skin while the system is in use. The second distance is the non-zero distance between the opening / skin and the detector (or the optical system upstream of the detector (if such an optical system is available)). The term optical system can specifically refer to a lens here.

In a plurality of embodiments, the sensor may include one or more of a silicon-based sensor and an InGaAs-based sensor.

In certain embodiments, the detector includes 2D cameras such as the CCD (or CMOS) cameras TD-Next 5620 M7_1A and TD-Next 5640 M12_3B. Each pixel may essentially consist of three pixels for blue, green, and red, respectively. It can provide the detector with the intensity of the blue, green, and red channels separately.

In a plurality of embodiments, the detector may have a detector area of about 10 * 10 mm ² . The detector may have as much as 1 megapixel or more.

In a further embodiment, the sensor may further include a focused lens configured upstream of the detector (and downstream of the sensor window). The focused lens can be configured to have focus on one side of the detector and / or focus on the skin on the other side of the lens. The lens can allow a good image of the skin in the detector.

In some embodiments, the sensor may further include apertures configured upstream of the detector and upstream of the focusing lens. This can further increase the resolution. Apertures may have diameters selected from the range of 0.1-5 mm, more specifically 0.1-2 mm, such as 0.1-5 mm, in a plurality of embodiments.

The optical axis of the system may be configured perpendicular to the detector. The optical axis of the light source is reflected by a mirror at distance d2 (such as the skin), propagates through the center of the aperture, and then reaches the detector (and reaches the edge of the detector surface). It can be defined as being on the same line as the light source. Therefore, the sensor is configured to provide light from a light source having an optical axis (OL) below an angle (α) with respect to the optical axis (O2) of the detector selected from the range of 10-80 °. Therefore, the angle α can also be determined as the incident angle. Being perpendicular to the detector (surface) can essentially coincide with being perpendicular to a mirror at distance d2 (such as skin). The mirror and detector surfaces may be configured essentially parallel. Similarly, the aperture and detector surface (and mirror) may be configured essentially parallel. During use, the optical axis of the sensor (system) is therefore constructed essentially perpendicular to the skin (and the detector (surface)).

As mentioned above, the sensor has a sensor opening downstream of the (iii) light source and upstream of the detector for the propagation of the light from the light source from the sensor and for the inlet of the reflected sensor light into the sensor. Including more parts. For example, the system may include a wall with a sensor opening. The system may also include a distance holder or other element protruding from the system, which allows for placement of the skin that will be sensed at a given distance from the sensor (and window; see below). do. For this purpose, the openings may have dimensions that prevent substantial bulging of the skin into the sensor openings. Therefore, by defining the sensor opening, the distance between the skin and the sensor and the distance between the skin and the window can be determined.

In particular, the sensor openings are configured such that the distance between the skin and the window is within a range of at least 1 mm, such as at least 2 mm, more specifically at least 3 mm.

Thus, the system is configured downstream of the light source, upstream of the sensor opening, and further upstream of the detector, with a second distance (d2) to the sensor opening being configured in certain embodiments. Also includes a sensor window that is at least 3 mm. As mentioned above, windows are, in particular, essentially flat windows. Further, in particular, the window is configured to prevent water from entering the sensor through or at the edge of the window.

In addition, the window is made of a material that transmits the light of the light source. Suitable light-transmitting materials are PE (polyethylene), PP (polypropylene), PEN (polyethylene terephthalate), PC (polyethylene), polymethylacrylate (PMA), polymethylmethacrylate (PMMA) (Plexiglas or Perspex), acetic acid. Cellulose butyrate (CAB), silicone, polyvinyl chloride (PVC), polyethylene terephthalate (PET), including (PETG) (glycol-modified polyethylene terephthalate) in one embodiment, PDMS (polydimethylsiloxane), and COC (cyclic olefin copolymer). It may contain one or more materials selected from the group comprising permeable organic materials, such as being selected from the group comprising. In particular, the light-transmitting material is, for example, polycarbonate (PC), poly (methyl) methacrylate (P (M) MA), polyglycolide or polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL). , Polyethylene adipate (PEA), Polyhydroxy alkanoate (PHA), Polyhydroxybutyrate (PHB), Poly (3-hydroxybutyrate-co-3-hydroxyvaleric acid) (PHBV), Polyethylene terephthalate (PET), Polybutylene Aromatic polyesters such as terephthalate (PBT), polytrimethylene terephthalate (PTT), polyethylene naphthalate (PEN) and the like or copolymers thereof may be included; in particular, the light transmissive material may include polyethylene terephthalate (PET). Therefore, the light-transmitting material is, in particular, a polymer light-transmitting material. However, in another embodiment, the light transmissive material may include an inorganic material. In particular, the inorganic light transmissive material can be selected from the group comprising glass, (molten) quartz, transmissive ceramic materials, and silicone. Hybrid materials containing both inorganic and organic moieties can also be applied. In particular, the light transmissive material comprises one or more of PMMA, transparent PC, or glass. In particular, the material is selected from the group comprising glass and polymethyl methacrylate.

In addition, the sensor window is particularly transparent. Such a window may have a relatively large mean free path for a wavelength of interest, such as the wavelength of light from one or more light sources. Therefore, in a plurality of embodiments, the mean free path considering only the scattering effect may be at least 5 mm, such as at least 10 mm with respect to the light of the light source. The term "mean free path" is, in particular, the average distance that a ray will travel before experiencing a scattering event that will change its direction of propagation.

The short distance between the sensor window and the skin appears to be relatively detrimental to the sensor signal, as ghost spots can be relatively prominent. In particular, the second distance is at least 3 mm, and more specifically at least 4 mm. In certain embodiments, the second distance (d2) is selected from the range of 4-10 mm. In such embodiments, the ghost spot may not be observed by the detector in nature.

In particular, the distance (d2) and the sensor window thickness (d4) of the sensor window are chosen to avoid direct specular reflection from the cover glass to the detector. The position of the skin (during use of the device) can be estimated or predicted for a given sensor, and as a result, the optimum second distance (d2) and sensor window thickness (d4) can be determined. can.

In a plurality of embodiments, the sensor window thickness can be optimized (eg, via simulation) based on a predetermined second distance d2, and the sensor window having the optimized sensor window thickness (sensor). Can be placed in a position where a second distance d2 can be obtained.

Alternatively, in a plurality of embodiments, a sensor window that can be optimized (eg, via simulation) for a second distance based on a predetermined sensor window thickness and has an optimized sensor window thickness. It can be placed in a position where an optimized second distance d2 can be obtained (while the sensor is in use).

In a further embodiment, the sensor window thickness and sensor window position can be optimized (via simulation) based on a predetermined second distance range and based on a predetermined sensor window thickness range. A sensor window with an optimized sensor window thickness can be positioned so that an optimized second distance d2 is obtained (while the sensor is in use).

The sensor opening may have essentially any (cross-sectional) shape downstream of the sensor window. However, in particular, the sensor opening has one or more curved (cross-sectional) shapes, such as an ellipse, and is essentially circular. As mentioned above, the sensor opening may not be too large. In certain embodiments, the sensor opening has a circular equivalent diameter selected from the range of 1-65 mm, particularly 1-20 mm, such as at least 3 mm. The equivalent circle diameter (or ECD) of an irregular two-dimensional shape is the diameter of a circle of equivalent area. For example, the equivalent circle diameter of a square having an edge a is 2 * a * SQRT (1 / π). As shown, the sensor openings may be particularly circular.

Good results are obtained with window thicknesses in the range of about 0.1-20 mm. Thus, in a plurality of embodiments, the sensor window has a sensor window thickness (d4) selected from the range of 0.1 to 20 mm, such as the range of about 1 to 10 mm. In particular, the thickness of the sensor window is essentially constant across the window.

By using the conditions described herein, ghost spots are reduced or even reduced essentially, resulting in more reliable sensor results, for example as a result of higher signal / background ratios. .. The rays that cause ghost spots are scattered and even better results can be obtained. Thus, in certain embodiments, the sensor window includes a central portion and a peripheral portion, the optical axis (O2) of the detector passes through the central portion, and the peripheral portion comprises an anti-glare element. The anti-glare element may include surface scatter and / or bulk scatter features. The anti-glare element may include irregular or regularly shaped structures on a portion of the surface of the sensor window and / or scattered particles within the window. In particular, the optical axis of the light source also passes through the central portion (that is, the light of the light source on the same line as the optical axis is not scattered by the antiglare element). The central portion is essentially free of such anti-glare elements and may therefore be inherently transparent. The peripheral area is particularly translucent.

In particular, the peripheral part (hence) surrounds the central part. The former may be about 5 to 90% of the total area of the peripheral part and the central part, such as 10 to 50% of the total area (of the sensor window) and 10 to 80%, and the latter may be about 5 to 90%. It may be about 10 to 95% of the total area, such as 50 to 90% and 20 to 90%. In particular, in embodiments, the area of the central portion is approximately equal to or greater than the area of the peripheral portion. However, in other embodiments, the area of the central portion is approximately equal to or smaller than the area of the peripheral portion.

Thus, in a plurality of embodiments, a portion of the outer surface of the window and / or a portion of the surface directed at the detector of the window is a structure that provides surface roughness (also as a "surface feature" herein. (Shown) may be included. These structures can be random and / or regular in shape. In addition, these structures may be randomly arranged and / or regularly arranged. Thus, in a plurality of embodiments, the sensor window includes an upstream surface and a downstream surface, and one or more of the upstream and downstream surfaces in the peripheral portion is particularly selected from the range of 40 to 500 nm, and so on. It has a root mean square surface roughness selected from the range of ~ 1000 nm.

In a plurality of embodiments, the surface feature may have an average cross-sectional circle equivalent diameter selected from the range of 40 nm to 100 μm. Furthermore, the average distance between adjacent surface features is 5 times or less the diameter equivalent to the average cross-sectional circle. In certain embodiments, the surface features are arranged in a configuration that fits at least about 80% of the highest theoretical packing possible, such as at least 90% of the highest possible theoretical packing. For example, assuming a surface feature with an essentially circular cross section, the closest packing can be obtained with a hexagonal arrangement of surface features, which is essentially 100 of the highest theoretical packing possible. May bring. The highest possible theoretical packing is less than 100% unless surface features that perfectly match each other are used, such as cubes with the same cross-sectional shape (parallel to the plane of the window).

In certain embodiments, the system may further include an analytical system. The analysis system is configured to rely on the sensor signal of the sensor to generate the corresponding skin sensor value. The analysis system and sensor can be integrated into a single device such as a skin cleansing device, a skin rejuvenating device and the like. Thus, in a plurality of embodiments, the system includes a skin care device such as a skin cleansing device, a skin rejuvenating device, etc., and the skin care device includes a sensor and an analytical system. The analysis system can convert the signal of the sensor, in particular the signal of the detector, into a signal that may have useful information for the user, such as a display of skin gloss on an indicator unit (such as a display or LED bar). The skin sensor value can be a skin parameter that can be further processed into a skin parameter based on a predetermined relationship between the skin sensor value and the skin parameter.

However, in other embodiments, the sensor may be included by another device connected to the analysis system by wire or wirelessly. For example, such an analysis system may be included by a smartphone. For example, the App can be used to read the sensor and display the skin sensor value based on the sensor signal generated by the sensor. Thus, in yet another embodiment, the system comprises (i) a skin care device comprising a sensor and (ii) a second device functionally coupled to the skin care device, the second device being an analytical system. including. The term "analytical system" can also refer to systems with multiple interrelationships. For example, the sensor may (further) include a processor, or an external device may include a processor capable of communicating with each other. The processor of the sensor can provide a sensor signal, based on which the processor of the external device produces a skin sensor value indicating skin gloss / oiliness.

The sensor signal may be a detector signal. In other embodiments, the sensor signal may be a processed detector signal. Thus, the phrase "based on a detector signal" can also refer to a processed detector signal in a plurality of embodiments. Based on the sensor signal, i.e. essentially based on the detector signal, the analytical system can provide the corresponding skin sensor value.

If the system includes a functional device such as a skin cleanser or skin rejuvenation device, this device will rely on the sensor signal (or skin sensor value) of the sensor (to detect gloss) to perform its actions. It may be configured in. For example, upon reaching a certain lower or upper threshold of skin gloss (or skin oiliness), the functional device can provide the user with a signal such as an acoustic or vibration signal. Alternatively or additionally, the functional device can reduce or increase certain actions depending on the sensor signal, such as increasing or decreasing skin massage depending on the sensor signal.

The terms "upstream" and "downstream" are the first in a beam of light from a light generator, particularly with respect to the placement of items or features related to the propagation of light from the light generator (here, in particular a light source). The second position in the beam of light closer to the light generating means is "upstream" and the third position in the beam of light further away from the light generating means is "downstream". When the light is reflected off the sensor, the light rays propagate from the skin to the detector. Thus, with respect to the detector, essentially any element between the sensor window and the detector is upstream of the detector; with respect to the light source, between the light source and the sensor window or between the light source and the skin. Any element is downstream of the light source. The sensor window is located downstream of the light source, but can be considered to be located upstream of the detector. The sensor window is upstream of the sensor opening because the light from the light source propagates through the sensor window (towards the skin). For the detector, the sensor window is downstream of the sensor opening (because the light travels towards the detector surface). During use, some of the light from the light source passes through the sensor, through the sensor opening, and is received by the skin. Therefore, the skin receives the light of an unpolarized light source through the sensor window. At least a portion of the light reflected by the skin passes through the sensor aperture, sensor window, and any optical system and is received at the detector surface.

Accordingly, in another further aspect, the invention also provides a method of sensing skin gloss, which provides light from a light source to the skin in the system defined herein and is further reflected by the skin. Includes sensing the reflected light from the source with the system.

The method is performed using a sensor on the skin, such as the housing including an opening on the skin, thereby a second of the skin and the detector or its last optical system during operation. There is a distance.

In particular, the method is a non-medical method. In particular, the method is a cosmetic method.

In another further aspect, the invention also provides a data carrier in which program instructions are stored, the method defined herein, when the program instructions are executed by the system defined herein. To execute. For example, for this purpose, the system may include a processor.

As mentioned above, the system may include a modulator. The splitter is configured to allow only one or more specific polarizations to enter the detector. Thus, in certain embodiments, the sensor comprises a stator configured upstream of the detector. In particular, the polarizing element includes one or more of (i) a segmented polarizer and (ii) a spatially variing polarizer. This makes it possible to reduce the effect of the (rotational) position of the detector, especially when the light sources are driven sequentially. In this way, the sensor can detect the reflected light as a function of the light source. With different polarizations of the modulator, the system may be more sensitive. In particular, the modulator is configured downstream of the sensor window. If a lens is available, the transducer may be configured downstream of the lens (where the lens is configured upstream of the detector (surface)). Thus, the modulator receives, in particular, the reflected unpolarized light and directs the polarized light towards the detector.

Thus, in certain embodiments, the device comprises a sensing mode and the light source is configured to sequentially provide the light of the light source. In a further specific embodiment, the detector may be configured to sequentially detect the light of a reflected light source sequentially generated by the light source, and may be further configured to generate a corresponding detector signal. good. As mentioned above, the system further comprises an analysis system, the analysis system is configured to depend on the sensor signal of the sensor to generate the corresponding skin sensor value, and in certain embodiments, the skin sensor value is. , Based on the average of each detector signal.

In a plurality of embodiments, the segmented splitter comprises a pixelated wire grid modulator having two or more pixels with different polarization directions. Here, the term "pixel" can also refer to an area. In particular, the sensor contains n light sources, such as four light sources, and the segmented splitter has n pixels with polarization directions perpendicular to each other, such as two sets of two pixels (for four light sources). Includes pixelated wire grid modulator. As mentioned above, the value of n is at least 2, especially 3 or 4 or more.

In a plurality of embodiments, the spatial change modulator comprises one or more of the azimuth change modulator and the radial change deflector, in particular allowing more emitters to be configured very close to each other.

Best results can be obtained near the blue star angle. Thus, in a plurality of embodiments, the sensor is configured to provide light from a light source having an optical axis (OL) under an angle of incidence (α) to the skin at a third distance (d3). α) is selected from the range of 50-60 °, and more specifically, the incident angle (α) is selected from the range of 52-56 °.

Thus, among others, in the present specification, in continuous illumination from a plurality of unpolarized light emitting elements that illuminate the skin at an incident angle (essentially) equal to the Blue Star angle or polarization angle, and in the detection path. Skin gloss measuring systems and methods using segmented or spatially variable polarizing elements are provided.

Particularly good results can be obtained if (hence) the light sources are driven sequentially. Since the light sources are configured at different locations, the reflection and polarization behavior, as well as the angle dependence of the reflected light, are thus further (which can result from non-uniformity of the skin structure and / or illumination). Information can be provided and / or it may be possible to reduce the sensor's dependence on rotational position on the skin.

Thus, in certain embodiments, the device comprises a sensing mode and the light source is configured to sequentially provide the light of the light source.

For example, the sensor may have a measurement frequency in the range of 0.1 * n-100 * n Hz, where n is the number of light sources. For example, at 1 * n Hz, every second, all light sources continuously illuminate the skin, and the detector measures (continuously) possible reflections based on each light source.

Of course, the use of multiple light sources may also allow for a subset of two or more light sources. For example, if four light sources are used, it may be possible to have two sets of two light sources, which are configured facing each other (with a detector in between). The set of light sources is alternately switched on and off.

A combination of such methods can also be applied, eg, the composition of a set of light sources can be changed in time. For example, in one mode, the light sources are sequentially dealt with during a given time, and then at a given time, the light sources are dealt with as a group. Such modes may include repetitions of each of these predetermined times. All kinds of lighting schemes can be used to make more reliable measurements of skin gloss.

The detector signal may be an average over the signals produced by each light source. Thus, in another further embodiment, the detector is configured to sequentially detect the reflected light from the light source, which is sequentially generated by the light source, and is further configured to generate a corresponding detector signal, the system. , The analysis system is configured to depend on the sensor signal of the sensor to generate the corresponding skin sensor value, the skin sensor value being based on the average of the respective detector signals. Therefore, especially the detector signal is processed first and then averaged. In this way, the detector signal may be an average over the signals produced by each light source.

As mentioned above, the system may include at least three light sources. Furthermore, as described above, in the plurality of embodiments, the sensor has a sensor optical axis (O2), and the light source is configured to be rotationally symmetric with respect to the sensor optical axis (O2).

In a further specific embodiment, as described above, the system may further include an analytical system, which is configured to depend on the sensor signal of the sensor to generate the corresponding skin sensor value. .. There can be many ways in which sensor signals can be generated. Although many low-cost devices have been reported for home use, gloss measurements using these devices appear to be non-quantitative and correlate with subjective perception and reference device measurements. May not have. The method of estimating gloss may be based on counting the number of white pixels above a certain threshold in a camera image obtained using unpolarized illumination. However, gloss estimation based on the number of white pixels depends on the intensity level of incident light (and its variations), thresholds, and changes in the optical properties of the skin (changes between and within individuals), which is less desirable. Seems to be.

In the following, some specific embodiments that may provide more reliable results are described.

Thus, in a plurality of embodiments, in particular the system is configured to create an image of the skin using a detector, the image of the skin from a first region where maximum intensity is perceived and a first region. The first region and the second region do not overlap, including the second region separated by the first image distance, and the system follows the path between the first region and the second region. It is further configured to generate skin sensor values based on the intensity dependence of the reflected light source. The image may have an image area. The first and second regions may be 0.05 to 15%, for example 0.05 to 30%, such as 0.1 to 10% of the image region. Further, the first image distance, i.e., the distance between the first and second regions, or more precisely, the shortest distance between the boundaries of these two regions, is at least the first region or the first. It may be as large as the area size of 2 areas. In general, the first and second regions may be essentially the same. Optionally, the regions may be different, but then correction factors may be applied. Moreover, in general, these areas are chosen as squares or rectangles, especially squares. The region where the maximum intensity is perceived may be the region of the image where specular reflection essentially occurs, that is, the region of the image where the light from the light source is reflected like a mirror and detected by the detector.

Therefore, the first image distance is in the range of 0.05-30% square root of the image area, such as 0.05-15% square root of the image area, such as 0.1-10% square root of the image area. It may be inside. In particular, the distance between the first region and the second region is the square root of at least 5% of the image region. It should be noted that the image area does not have to have a fixed value, but may depend on the magnification, for example.

Further, the term "creating an image" and similar terms do not necessarily include creating the actual image at that moment, but read the detector values at different locations across the detector surface. Note that this can also be pointed out.

Information that can be obtained from two regions and / or from (straight) lines or regions between those two regions can provide information about glossiness, especially if the system is calibrated. , It seems possible to be able to quantify skin gloss (including skin oiliness) (see also below).

Thus, in some embodiments, the system produces skin sensor values based on the slope of the curve determined by the intensity of the reflected light from the light source along the path between the first and second regions. It may be configured as follows. Therefore, it appears that useful skin gloss values can be generated based on the slope of the curve or the angle of the curve.

Alternatively or additionally, the system generates skin sensor values based on the area under the curve determined by the intensity of the reflected light from the light source along the path between the first and second regions. It may be configured as follows. Therefore, it appears that useful skin gloss values can be generated based on the area under the curve or the angle of the curve. The route can also be shown as a straight orbit or a straight line.

Further, alternative or additionally, the system may be configured to generate skin sensor values based on the number of pixels in the image above a predetermined threshold. Therefore, it also seems possible to generate useful skin gloss values based on the number of pixels above the threshold.

Further, alternative or additionally, the system may be configured to generate skin sensor values based on the average number of pixels in the image above a predetermined threshold, each weighted by the corresponding pixel intensity. Therefore, useful skin gloss values can be generated based on the number of weighted pixels that exceed the threshold.

Further, alternative or additionally, the system may be configured to generate skin sensor values based on the relationship of the integrated intensities of the first region and the second region. Therefore, the mirror-to-diffusion intensity ratio of each of these ratios can also be used to generate skin gloss values. For example, if the system is calibrated in the specular and diffuse regions in nature, the skin gloss parameter can be obtained from the mirror-to-diffuse intensity ratio of each of these ratios.

Further, alternative or additionally, the system is configured to define a binary large object (“blob”) in the image, and the system is one or more of the average size and maximum size of the binary large object in the image. It is configured to generate skin sensor values based on. Therefore, useful skin gloss values can also be generated based on the number of blobs and / or the size of the blobs. Therefore, in this embodiment, the number of white pixels itself is not used, but a blob is defined. Thus, thresholds can also be set for those blobs, such as at least a number of adjacent pixels over a particular intensity threshold.

In the above embodiments, calibration has been described many times. In particular, system calibration, or more precisely sensor calibration (actually, therefore, detector calibration), may be useful for the quantitative assessment of skin gloss or oiliness. This calibration can be done after the sensor is manufactured. Alternatively or additionally, the calibration may be software-implemented for each sensor based on one or more previous calibrations of the example sensors. Calibration may also be part of the measurement process or may be scheduled on a regular basis. In certain embodiments, the calibration is applied once after production of the sensor. In addition, the system may include a control routine that can update the calibration based on the sensor parameters of the reference sensor or, for example, based on signal drift and the like.

In certain embodiments, the system is configured to rely on the sensor signal of the flatfield corrected sensor to generate the corresponding skin sensor value. Flat field correction is a technique used to improve the quality of digital imaging. Flatfield corrections are used in particular to compensate for artifacts from 2D images caused by changes in sensitivity between detector pixels and / or distortion of the optical path due to illumination and detection inhomogeneities. As mentioned above, the flat field correction may be based on measurements using pure diffusion criteria, such as, for example, a diffusion standard plate such as Spectralon. Based on such measurements, flat field corrections may be provided, which may be used in any measurement (described herein).

In another further embodiment, the system is configured to rely on the sensor signal of the sensor to generate the corresponding skin sensor value based on the average of the respective signals of the red, green, and blue channels of the detector. Will be done.

Embodiments of the present invention will then be described merely as examples with reference to the accompanying schematics. In the schematic, the corresponding reference symbols indicate the corresponding parts.
It is a figure which roughly described one aspect of the system. It is a figure which roughly described one aspect of the system. It is a figure which showed the unpolarized reflection and transmission at the interface. FIG. 3 is a schematic representation of possible polarization schemes for illumination and detection. It is a diagram showing measurements on the skin using an ejection glass window in contact with the skin, where the ghost spots from the glass window are stronger than the intensity of light detected from the skin and are therefore not a possible solution. It is a diagram showing an antireflection coated glass window between the optics and glossy paper, which reflects specular reflection, but the image looks green due to the dependence of the angle of incidence and wavelength selection on the insulator coating. It is a simulation (left) schematically showing a prototype using a glass window at a distance of 3 mm or more from the skin, and a diagram showing that the PMMA window and the reflection spot from the skin are on the sensor (right). It is a figure which showed the simulation which shows the shift of the reflected spot (ghost spot) from the PMMA window on the sensor with respect to the spot reflected from the skin. , Dependence of S / D ratio (mirror surface / diffusion) on the glass thickness (GT) of the glass window (ranging from 0 to 3 mm) and for different gloss values (Gloss-20, 40, 100 a.u.). Reference G indicates glossiness in% (20, 40, and 100%); the distance of the glass window from the skin was 0.1 mm. For samples with a gloss value of 20%, which is a range of gloss values suitable for the skin, the effect of ghost spots can be minimized by using a thick glass window. With a glass thickness of 0 mm, there is (hence) no sensor window. It is the figure which showed the dependence of the S / D ratio with the gloss value (Gloss ~ 0 to 100 au) of a sample, and the distance from the skin of a glass window was 0.1 mm. The effect of ghost spots is more important for low gloss samples, and skin gloss values are expected to be within this range (~ 10-20% gloss units). Here, the reference symbol G indicates a device including a glass window, and the reference symbol NG indicates a device having no such glass window. Further, G on the X-axis indicates glossiness (%). It is the figure which showed the dependence of the S / D ratio to the gloss value (Gloss ~ 0 to 100 a.u) of a sample, and the influence of a ghost spot is all the gloss when the distance from the skin exceeds 2 mm. Less important to the sample; the reference symbol G again indicates gloss (%), 20, 40, and 100%, respectively. Further, d on the X-axis indicates the distance (mm) between the skin and the window. It is a figure which roughly drew further embodiment. The schematic is not always on scale.

FIG. 1a schematically depicts a system 1 comprising a sensor 100 for measuring skin parameters (selected from one or more of the groups comprising skin gloss and oiliness). The sensor 100 includes a plurality of spatially separated light sources 110 configured to provide light 111 for the light source, and a detector 120 configured at a first distance d1 from each of the light sources 110. The sensor 100 provides, in particular, light 111 of a light source having an optical axis OL under an incident angle α selected from the range of 10-80 ° to the skin at a third distance d3, and further a reflected light source. It may be configured to detect the light 111 of. In particular, the sensor 100 may include at least three light sources 110 here, only two are drawn for comprehension so that the light source 110 provides light 111 for an unpolarized (visible) light source. It is configured. The first distance d1 can be selected, for example, from the range of 10-80 mm, and the detector 120 is configured to detect polarization. The dashed line S indicates the skin. Reference number 150 indicates a sensor window, and reference number 151 indicates a material for the sensor window. The sensor window 150 has a sensor window thickness d4 selected, for example, from the range of 0.1 to 20 mm.

The detector 120 may include, for example, a 2D camera 101. Further, the sensor 100 may include a focusing lens 102 configured upstream of the detector 120 and an aperture 103 configured upstream of the detector 120 and upstream of the focusing lens 102 (and downstream of the sensor window 150). .. The aperture 103, in a plurality of embodiments, has a diameter D1 selected from the range of 0.1 to 0.8 mm. The focusing lens may be f5 to 15 mm, for example, a 10 mm lens. In addition, the system may include a second focusing lens, the combination of which lens with the first lens can provide the desired field of view and depth of focus for the entire system (see, eg, FIG. 1A). ). The light source 110 is configured to provide light 111 from an unpolarized white light source.

As shown in FIG. 1a, the system 1 may further include an analysis system 2, which is configured to depend on the sensor signal of the sensor 100 to generate the corresponding skin sensor value. ing.

The analysis system 2 may be included by a device that also includes the sensor 100 (see also FIG. 1b) or by a separate device. FIG. 1a also schematically illustrates such an embodiment, in which the system 1 includes a skin care device 3, the skin care device 3 includes a sensor 100, and a second device 200 functionally comprises the skin care device 3. Combined, the second device 200 includes an analysis system 2.

The sensor 100 includes an opening 107. This opening may be particularly flat, i.e., its perimeter may have edges that are essentially flat. In this way, the sensor can be configured flat on the skin. The opening 107 may have a diameter D2 or a corresponding diameter D2, which may be in the range of about 10-30 mm.

The reference number O2 points to the optical axis of the sensor 100. If the sensor 100 is configured on the skin, this axis may essentially coincide with a perpendicular to the skin.

The reference number TS indicates the upper surface of the sensor. This may be a flat surface. Reference numeral LB indicates a direct light blocker, which is configured to prevent light from a light source from reaching the detector without a single reflection and / or is not reflected by the skin. The light that reaches the detector 120 reflected by the other internal surface of the sensor can be reduced. Reference number 104 refers to a polarizing element.

The O2 axis can essentially coincide with the perpendicular to the skin.

In particular, the TS can indicate the top surface of the housing 105. The top surface TS can actually determine the second distance d2 from the skin to the detector 120 or its last lens. Here, the upper surface TS includes the opening 107. The opening size of the opening can also be indicated as a field of view (FOV). The field of view is also indicated herein by reference symbol FV. The field of view (FOV) can be defined as a range of angles at which incident radiation can be collected by the detector. It should be noted that the opening or housing opening 107 may be circular, square or rectangular, or may have a different shape. The reference symbol FVA indicates a viewing angle. The reference symbol TT indicates a total track that is the distance from the opening 107 (ie, the moving skin) to the top surface of the support that receives the light source 110, which distance is generally applied by a solid light source such as an LED. Therefore, it is essentially the same as the distance to the top of the light source 110. The total track is in the range of 10 to 200 mm, for example, in the range of 10 to 30 mm, in the range of 10 to 80 mm, or in the range of 40 to 80 mm, in the range of 40 to 200 mm, etc. May be good. The total track TT is longer than the second distance d2. The detector 120 and any optical system may have a height in the range of about 1-50 mm, such as 1-20 mm. A second distance d2 is guaranteed when the sensor 100 is configured on the skin, as can be derived from the drawings. Thus, the sensor 100 may include a distance holder (as depicted), such as the housing 105, or optionally, a housing and another distance holder. As mentioned above, the visible light source light 111 is particularly unpolarized. Therefore, the light 111 of the light source is particularly the light of an unpolarized light source. It should be noted that the optical axis O2 of the sensor 100 and the optical axis of the detector 120 can be essentially aligned. In addition, the optical axis O2 of the sensor and the net optical axis of all light sources 110 may coincide.

In general, the distance d2 can be defined as the distance between the opening that will be placed on the skin and the detector or its last optical system as seen from the detector.

Referring to FIG. 1a (and similarly FIG. 5), the light source is not directly behind the sensor window or directly behind the opening 107. Therefore, in particular, the distance between the light source and the optical axis O2 of the sensor is longer than the distance from the end of the sensor window 150 to the optical axis O2. Similarly, in particular, the distance between the light source and the optical axis O2 of the sensor is longer than the distance from the end of the opening 107 to the optical axis O2. In certain embodiments, the distance between the light source and the optical axis O2 of the sensor is greater than half the equivalent diameter of the sensor window 150. In another particular embodiment, the distance between the light source and the optical axis O2 of the sensor is greater than half the equivalent diameter of the opening 107. In the embodiments schematically depicted herein, the distance from the end of the opening 107 to the optical axis O2 is (generally) the distance between the end of the sensor window 150 and the optical axis O2 (essentially). Note that they will be the same.

The optical axis of the light source can be defined as the optical axis of the beam of light of the light source that can escape from the opening 107. As can be seen in FIGS. 1a and 5, the beam may have a different shape and then the beam generated by the light source may be reflected by the housing as part of the light. Well, optionally, after reflection (s), it also exits through the opening 107.

The distance d2 and the thickness d4 of the sensor window are specifically placed and calculated in such a way as to avoid direct specular reflection from the sensor window to the detector.

FIG. 1b schematically illustrates one embodiment of the system 1, where the system 1 includes a skin care device 3 such as a skin cleansing device, a skin rejuvenating device, etc., where the skin care device 3 includes a sensor 100 and an analysis system. 2 is included. The skin care device 3 may also include a display unit IU and / or a user interface UI. The reference symbol FA indicates a functional area such as an area that can be used to massage or exfoliate the skin.

When unpolarized light is reflected by the skin surface, the polarization characteristics of the reflected light depend on the illumination angle (Fig. 2). The two orthogonal linearly polarized states that are important for reflection and transmission are called p-polarization and s-polarization. The p-polarized light (from the German word parallel) has an electric field polarized parallel to the plane of incidence, and the s-polarized light (from the German word senkrecht) has a polarized light with respect to this plane. Is vertical. The reference symbol N indicates a perpendicular line (relative to the surface), and the reference symbol PI indicates an incident surface. Further, the reference symbol SK indicates an incident surface such as a skin surface. Reference symbols S and P indicate polarization.

The reflected light is unpolarized for illumination angles equal to 0 ° or 90 °, is partially (preferably S) polarized for illumination angles from 0 ° to 90 °, and is further polarized or It is plane (S) polarized for one illumination angle equal to the Blue Star angle.

The angle of incidence (0 ° and 90 °) at which the reflection coefficient of light having a (P) electric field parallel to the incident surface becomes zero and the reflected light at that angle is linearly polarized by the (S) electric field vector perpendicular to the incident surface. ) Is called the polarization angle or the blue star angle. The polarization angle or the blue star angle (θB) can be calculated based on Fresnel's equations. Fresnel's equation states that light with p-polarization (electric field polarized in the same plane as the incident light and surface normal) is not reflected when the angle of incidence is θ _B = 1 / tan (n ₂ / n ₁ ). I predict that. Here, n ₁ is the refractive index of the first medium (“incident medium”) through which light propagates, and n ₂ is the refractive index of another medium. For a glass medium (n ₂ ≈ 1.5) in air (n ₁ ≈ 1), the blue star angle with respect to visible light is about 56 °. For the optical arrangement disclosed in the present invention, the light is incident at the air-skin interface and the blue star angle is about 54 °. The preferred range is 50-60 °.

Thus, in a plurality of embodiments, segmented modulators (for a smaller number of emitters from 4 to 8) or spatial variation (eg, for a larger number of emitters greater than 12) in the detection path. A modulator can be used. In particular, the number of segments is equal to the number of emitters.

When the illumination angle is 0-90 °, the detection of partially (preferably S) polarized reflected mirror light, which is a measure of gloss, gets into this component using an S-polarizer in front of the camera. It can be strengthened by. For lighting schemes with multiple light sources, segmented or spatially variable modulators can be used.

Therefore, it is proposed herein to use camera systems and methods for the quantitative measurement of skin gloss (s) that are less dependent on the rotation angle of the sensor, among other things. The proposed invention, in a plurality of embodiments, is continuous illumination from three or more light sources (unpolarized illumination) and continuous detection using a single low cost camera sensor (polarization detection). ) Is used. The gloss value is estimated based on the average number of pixels estimated from multiple independent images taken along different directions. A schematic diagram of the optical arrangement of the camera prototype is shown in FIG. The image processing method (algorithm) used to estimate the gloss value can be based on the number of white pixels or the slope of the intensity change along the optical axis normalized to the maximum after flat field correction, but others. Options are also possible (see also below).

Underestimation of gloss resulting from rotation-related effects associated with the use of a single emitter, based on experimental data measured ex-vivo skin and in-vivo with a rectangle, is symmetrically placed in a ring illumination configuration. It can be minimized by using continuous illumination utilizing three or more emitters (such as a triangular configuration for N = 3 and a rectangular configuration for N = 4). This is illustrated (Fig. 3). When multiple emitters are used at the same time, the gloss value depends on the angle of rotation and the effect is primarily dictated by the number of white pixels in the area where the intensity distributions from the multiple emitters overlap. In the present specification, A, B, and C indicate light sources arranged in a ring shape.

For home use, especially in an environment such as a bathroom, the sensor is expected to be waterproof and clean. This can be achieved by using a transparent glass window that shields the entire illumination and detection optics. Typically, in a skin sensor such as a dermatoscope, the glass window is placed in contact with the skin. However, when the glass window is used in contact with the skin, the sensor signal is dominated by "ghost spots" resulting from Frenel reflections at the two interfaces of the glass window (air-glass and glass-air interface). become. This ghost spot does not carry any information from the sample (skin) and is referred to as the "undesirable reflex". For a given lighting condition, the ghost spot is expected to be stronger than the light reflected from the skin due to the higher reflectance coefficient of the glass-air interface compared to the effective reflection generated from the skin. In addition to this, ghost spots from the glass can interfere with the signal coming from the skin and can overlap with the signal coming from the skin, resulting in poor estimation of skin oil / gloss. Become.

To solve this problem resulting from ghost spots, we tested the following solutions:
1. 1. Glass window above the sensor in contact with the skin (Fig. 4a):
2. 2. Angled window: This solution can work with sensors that use one or two emitters that can optimize tilt for two emitters. However, this solution is not optimal for systems that use more than two emitters for lighting.
3. 3. Anti-reflective coatings: Anti-reflective coatings do not work in combination with these wide range of illumination angles, especially wideband light sources (Figure 3). AR-coated (dielectric-coated) glass was used on high-gloss paper to test whether ghost specular reflections originated from the sensor. Due to the wavelength cutoff frequency (usually about 700 nm), the sensitivity of the sensor will shift to a lower wavelength, reducing the red sensitivity and the resulting image (FIG. 4b) will appear greenish. Therefore, I observed that it was not a promising solution to this problem.

Among other things, the present invention proposes a low-cost, waterproof, pollution-free sensor for measuring skin properties. The proposed invention is based on the use of a transparent window, preferably having a thickness of more than 3 mm and further at a distance of a few mm, preferably more than 3 mm from the skin. This solution causes Fresnel reflections from the window (undesirable ghost spots (indicated by the reference symbol GS in FIG. 5)) to deviate from the sensor as compared to the reflection intensity from the skin (FIG. 5). In a preferred embodiment, the transparent window uses a rough surface so that the Fresnel reflected light from the air-glass interface is distributed over a range of angles so that the effective impact generated by the ghost spot is significantly reduced. .. The simulation calculates photometric and radiative quantities to perform a complete illumination and detection analysis. The optical layout of the system used in the simulation was based on the prototype configuration developed for oil / gloss measurements. A schematic diagram of the camera prototype and system layout used in the simulation is shown in FIG. The result as a function of the distance from the window to the skin is depicted in FIG. It is clear that as the distance from the window to the skin increases, the ghost spot GS moves away from the spot reflected from the skin.

Intensity distributions and corresponding intensity plots in camera sensors obtained for samples with different gloss values are shown for FIGS. 7-9 with different configurations. The mirror-to-diffusion intensity ratio ranges from the following parameters: glass window thickness, distance from skin, and gloss value (mirror (Gloss-100 a.u)) to diffusion standard (Gloss-100 a.u). Estimated as a function of the sample.

FIG. 10 schematically illustrates an embodiment in which the sensor window 150 includes a central portion 152 and a peripheral portion 153. The optical axis O2 of the detector 120 and the optical axis OL of the light of the light source pass through the central portion 152. Peripheral portion 153 includes an anti-glare element 160. The central part essentially does not contain such anti-glare elements. The sensor window 150 includes an upstream surface 154 and a downstream surface 155. One or more of the upstream surface 154 and the downstream surface 155 in the peripheral portion 153 may have such an anti-glare element having a root mean square roughness particularly selected from the range of 40-500 nm.

The term "plurality" refers to more than one.

The term "substantially", such as in "substantially consisting of" herein, will be understood by those of skill in the art. The term "substantially" may also include embodiments such as "overall," "completely," and "all." Thus, in some embodiments, the adjective substantive can also be removed. Where applicable, the term "substantially" can also relate to 95% or more, in particular 99% or more, and more specifically to 99.5% or more, including 100%, and more. The term "comprise" also includes embodiments in which the term "comprises" means "consisting of". The term "and / or" specifically refers to one or more of the items mentioned before and after "and / or". For example, the expression "item 1 and / or item 2" and similar expressions may relate to one or more of item 1 and item 2. In one embodiment, the term "comprising" may refer to "consisting of", but in another embodiment, "at least a predetermined species and optionally one or more other". Having a seed "can also be pointed out.

Moreover, terms such as 1, 2, and 3 in the specification and claims are used to distinguish similar elements, not necessarily to describe order or chronological order. The terms so used are interchangeable under the appropriate circumstances, and the embodiments of the invention described herein are in an order other than those described or exemplified herein. It should be understood that it can be operated with.

The devices in the present specification are described, among other things, those in operation. As will be apparent to those skilled in the art, the invention is not limited to operating methods or operating devices.

The above embodiments illustrate, but do not limit, the invention, and one of ordinary skill in the art can design many alternative embodiments without departing from the appended claims. Note that there is. In the claims, any reference code placed in parentheses should not be construed as limiting the scope of the claims. The use of the verb "contains" and its conjugations does not preclude the existence of elements or steps other than those stated in the claims. Words such as "comprise" and "comprising" are not exclusive throughout the present specification and claims, except where the context expressly should be construed in other ways. In contrast, it will be interpreted as a comprehensive or exhaustive meaning; that is, "including, but not limited to,". The article "a" or "an" preceding an element does not preclude the existence of a plurality of such elements. The present invention can be carried out by hardware containing several distinct elements and by a properly programmed computer. In a device claim that lists several means, some of these means can be embodied by one item of the same hardware. The mere fact that certain means are described in different dependent claims does not indicate that the combination of these means cannot be used in an advantageous manner.

The invention also provides a control system capable of controlling an instrument or device or system or performing the methods or processes described herein. Furthermore, the invention is one or more of such instruments or devices or systems when performed on a computer that is functionally coupled to or contained by the instruments or devices or systems. We also provide computer program products that control controllable elements.

The invention further applies to devices that include one or more of the features described herein and / or shown in the accompanying drawings. The invention further relates to a method or process comprising one or more of the features described herein and / or shown in the accompanying drawings.

The various aspects discussed herein can be combined to provide additional benefits. Further, one of ordinary skill in the art will appreciate that embodiments can be combined and that three or more embodiments can be combined. In addition, some of the features can form the basis for one or more divisional applications.

Claims (17)

A system that includes a sensor that measures skin parameters, wherein the sensor is from (i) a plurality of spatially separated light sources configured to provide light from the light source and (ii) from each of the light sources. The first distance includes a detector configured at a first distance, the first distance being selected from the range of 5-80 mm, the sensor comprising at least three light sources, the light source being unpolarized. Configured to provide light from a light source, the sensor is (iii) downstream of the beam of light propagating from the light source and upstream of this beam of light of the detector to measure skin parameters. A sensor opening for propagating the light of the light source from the sensor towards the skin and for an inlet of the reflected sensor light into the sensor, the light source propagating from the sensor opening. The light is a sensor opening, which is the light of an unpolarized light source, and (iv) a sensor window of a material that transmits the light of the light source, which is configured downstream in a beam of light propagating from the light source. A sensor window configured upstream of this beam of light in the opening and further upstream in this beam of light of said detector, having a second distance to the sensor opening of at least 3 mm. Including, system. The system of claim 1, wherein the second distance is at least 4 mm. The second distance is selected from the range of 4-10 mm, the sensor opening has a circular equivalent diameter selected from the range of 1-20 mm, and the sensor window is in the range of 0.1-20 mm. The system according to claim 1 or 2, having a sensor window thickness selected from. The system according to any one of claims 1 to 3, wherein the first distance is selected from the range of 4 to 20 mm . The system of claim 4, wherein the first distance is selected from the range of 8-14 mm. The system according to any one of claims 1 to 5 , wherein the material is selected from the group comprising glass and polymethyl methacrylate. The sensor window comprises a central portion and a peripheral portion, the optical axis of the detector passes through the central portion, and the peripheral portion includes an anti-glare element, according to any one of claims 1 to 6 . System. The sensor window includes an upstream surface and a downstream surface, and one or more of the upstream surface and the downstream surface in the peripheral portion has a surface roughness of a squared average square root selected from the range of 40 to 500 nm. 7. The upstream surface is located closer to the light source in the light propagation direction of the light source, and the downstream surface is located farther from the light source in the light propagation direction of the light source. The system described. Including surface features, the surface features have an average cross-sectional circle equivalent diameter selected from the range of 40 nm to 100 μm, and the average distance between adjacent surface features is less than or equal to 5 times the average cross-sectional circle equivalent diameter. , The system according to claim 7 . The detector is configured to detect polarization, the sensor comprises a polarizing element configured upstream in the beam of light propagating from the light source of the detector, and the modulator is the segment (i). The system according to any one of claims 1 to 9 , comprising one or more of a chemicalist and a (ii) spatial change detector. The detector includes a 2D camera and the sensor is a focused lens configured upstream of the beam of light propagating from the light source of the detector and upstream of the focused lens of the light beam of the detector and the focused lens. Further comprising an aperture configured upstream in this beam of light, said aperture having a diameter selected from the range of 0.1-0.8 mm, said light source being an unpolarized white light source. The system according to any one of claims 1 to 10 , which is configured to provide light. The system according to any one of claims 1 to 11 , further comprising an analytical system configured to generate a corresponding skin sensor value depending on the sensor signal of the sensor. The system includes a sensing mode, wherein the light source is configured to sequentially provide light from the light source, and the detector is configured to sequentially detect light from a reflected light source sequentially generated by the light source. The system of claim 12 , wherein the skin sensor values are configured to generate a corresponding detector signal and are based on the average of the respective detector signals. The sensor has a sensor optical axis, the light source is configured to be rotationally symmetric about the sensor optical axis, and the sensor is the sensor optical axis of the detector selected from the range of 10 to 80 °. The system according to any one of claims 1 to 13 , wherein the system is configured to provide light from said light source having an optical axis below an angle with respect to. 14. The system of claim 14, wherein the angle is selected from the range of 20-60 °. A method of sensing skin parameters, wherein the system of any one of claims 1 to 15 is used to provide light from a light source to the skin, and the system is used to reflect off the skin. A method that involves sensing the light of a reflected reflected light source. A data carrier that, when executed by the system according to any one of claims 1 to 15 , stores a program instruction that causes the system to execute the method according to claim 16 .

Images